The following relates generally to memory systems and more specifically to self-referencing sensing schemes with coupling capacitance.
Memory devices are widely used to store information in various electronic devices such as computers, wireless communication devices, cameras, digital displays, and the like. Information is stored by programing different states of a memory device. For example, binary memory devices have two logic states, often denoted by a logic “1” or a logic “0”. In other memory devices, more than two logic states may be stored. To access the stored information, a component of the electronic device may read, or sense, the stored logic state in the memory device. To store information, a component of the electronic device may write, or program, the logic state in the memory device.
Various types of memory devices exist, including those that employ magnetic hard disks, random access memory (RAM), read only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others. Memory devices may be volatile or non-volatile. Non-volatile memory, such as PCM and FeRAM, may maintain stored logic states for extended periods of time even in the absence of an external power source. Volatile memory devices, such as DRAM, may lose stored logic states over time unless they are periodically refreshed by a power source. In some cases, non-volatile memory may use similar device architectures as volatile memory but may have non-volatile properties by employing such physical phenomena as ferroelectric capacitance or different material phases.
Improving memory devices, may include increasing memory cell density, increasing read/write speeds, increasing reliability, increasing data retention, reducing power consumption, or reducing manufacturing costs, among other metrics. In some cases, a reference voltage for reading a memory cell may be provided by a reference voltage source that is shared among many memory cells. In such cases, operations (e.g., read operations) may be sensitive to variations between one memory cell and another, and the memory device may be associated with relatively low sensing margins or be otherwise sensitive to read errors. In some cases, accessing a memory cell with a self-referencing sensing scheme may require several access operations on the memory cell to provide suitable reference signals for each of the potential logic states of the memory cell. Such sensing operations may be associated with relatively slow memory cell access times, or relatively high power consumption.